Polydextrose as Wall Material for Microencapsulation of Yacon Juice by Spray Drying

The juice from yacon roots was encapsulated by spray drying using polydextrose and gum Arabic as wall materials. The effects of the concentration of the encapsulating agents and drying temperature on total phenolics, antioxidant activity, fructooligosaccharides, moisture content, water activity, solubility, hygroscopicity, color, and morphology of the microparticles were investigated to assess the potential use of polydextrose as wall material. The microparticles produced with polydextrose showed retention of bioactive compounds and physicochemical characteristics similar to those produced with gum Arabic. The phenolic retention ranged from 73.67 to 85.49 %, and the antioxidant activity by DPPH varied from 80.78 to 90.58 %. The fructooligosaccharides have undergone little depolymerization into simple sugars even at high temperatures. With respect to the physicochemical characteristics, high stability (low moisture and water activity), low hygroscopicity, and high solubility were observed in the microparticles. The spray dried samples showed a hue angle close to 100, indicating yellow color of the particles. Regarding the microstructure, particle agglomeration was observed in both treatments, probably due to the hygroscopic characteristic of the spray dried powders.